Thursday, January 12, 2017

algebra precalculus - Does (plambda11)cdots(plambdam1) divide pn1?

Let p be a prime integer and n3 be a natural number such that pn1 has a primitive prime divisor. Also let n=λ1++λm such that n>λi1 for all i. I want to show that (pλ11)(pλm1) does not divide pn1.

This is my suggested argument for proving the statement when p>2:
Both of (pλ11)(pλm1) and pn1 are polynomials in p with the same degree. If (pλ11)(pλm1)pn1, we then have pn1=c(pλ11)(pλm1), where cN. Since p>2, pλi1>1 for all i. Therefore, the coefficient of pλ1+...+λm=pn in the expansion of the product mi=1(pλi1) is 1. Also the coefficient of pn in pn1 is 1, and so we must have c=1 . Therefore pn1=(pλ11)(pλm1). Now if we consider q to be primitive prime divisor of pn1, then q does not divide (pλ11)(pλm1), which is a contradiction. So if p>2, it is impossible for (pλ11)(pλm1) to divide pn1.

But as it was discussed in comments, it seems that my argument is not true.
Question 1: Does my argument work? If not, is there any possible way to prove the statement for p>2?
The remaining case is when p=2. According to the example mentioned in comments (21)(221)(231)261.
Question 2: Is there any example of a pair (n,p)(6,2) and a partition $\lambda=(1\leq\lambda_1\leq...\leq\lambda_mI would be grateful for any help.

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